I lost all my extensions. Plus, my browser is acting weird.

My browser lost all its extensions on all of my computer's user accounts. What's strange though is that on one account, Facebook Messenger still appears beside the search bar but does not appear in the add-ons manager, so I can't really disable or remove it. Also, my add-ons tab has the suspicious-looking DownnSave 5.2 and IIsave 4.6 which I don't recall installing.

A Delta Search tab that I don't remember installing has suddenly taken over the empty tabs. Like the Facebook Messenger extension, it also does not appear in the add-ons manager.

All of these problems still occur when I restart Firefox without add-ons and even after I have deleted the extensions.* files, compatibility.ini, and the add-ons.sqlite in the profile folders.

I considered using the Reset option in the Troubleshooting tab, but that would remove all my add-ons if I'm not mistaken. Is there anyway to fix the aforementioned problems without having to reset my browser.

My browser lost all its extensions on all of my computer's user accounts. What's strange though is that on one account, Facebook Messenger still appears beside the search bar but does not appear in the add-ons manager, so I can't really disable or remove it. Also, my add-ons tab has the suspicious-looking DownnSave 5.2 and IIsave 4.6 which I don't recall installing.
A Delta Search tab that I don't remember installing has suddenly taken over the empty tabs. Like the Facebook Messenger extension, it also does not appear in the add-ons manager.
All of these problems still occur when I restart Firefox without add-ons and even after I have deleted the extensions.* files, compatibility.ini, and the add-ons.sqlite in the profile folders.
I considered using the Reset option in the Troubleshooting tab, but that would remove all my add-ons if I'm not mistaken. Is there anyway to fix the aforementioned problems without having to reset my browser.

Chosen solution

Could you start by checking the Windows Control Panel, Uninstall a Program for recently installed junk that may have been bundled with one of your downloads? I recommend clicking the "Installed on" column heading to bring the most recent items to the top and connect the dots of different bundles.

Question owner

Correction 2: I forgot that Facebook Messenger is in the Services tab, not the Add-ons Manager, so please disregard that part of my question.

Update: Downnsave 5.2 and IIsave 4.6 seem to have been replaced by AlllSaveer 1.4 and CoupExttensiona 1.3 after I performed a system restoration.

Correction 2: I forgot that Facebook Messenger is in the Services tab, not the Add-ons Manager, so please disregard that part of my question.
Update: Downnsave 5.2 and IIsave 4.6 seem to have been replaced by AlllSaveer 1.4 and CoupExttensiona 1.3 after I performed a system restoration.

Chosen Solution

Could you start by checking the Windows Control Panel, Uninstall a Program for recently installed junk that may have been bundled with one of your downloads? I recommend clicking the "Installed on" column heading to bring the most recent items to the top and connect the dots of different bundles.

As for a Reset, your plugins will survive the process, as well as any system-installed extensions. The add-ons you will lose are extensions installed directly into that Firefox profile.

By the way, in case Firefox performed an automatic reset, could you check for desktop for an Old Firefox Data folder?

Could you start by checking the Windows Control Panel, Uninstall a Program for recently installed junk that may have been bundled with one of your downloads? I recommend clicking the "Installed on" column heading to bring the most recent items to the top and connect the dots of different bundles.
You may also need to do a vigorous scrub-down for malware. This article lists tools Firefox users have found helpful: [[Troubleshoot Firefox issues caused by malware]].
As for a Reset, your ''plugins'' will survive the process, as well as any system-installed extensions. The add-ons you will lose are extensions installed directly into that Firefox profile.
By the way, in case Firefox performed an automatic reset, could you check for desktop for an Old Firefox Data folder?

Question owner

Hi there jscher2000. Fortunately, I found a FEBE folder with most of my add-ons. However, I couldn't get a few of them back anyway because they're either corrupted or incompatible with Firefox 26. I'm just thankful that I didn't lose huge amounts of data. Also, the Delta Search tab somehow disappeared when I reinstalled my add-ons.

Anyway, your tips are still very helpful. I'll let you know when I've dealt with the malware.

Thanks, BTW :-)

Hi there jscher2000. Fortunately, I found a FEBE folder with most of my add-ons. However, I couldn't get a few of them back anyway because they're either corrupted or incompatible with Firefox 26. I'm just thankful that I didn't lose huge amounts of data. Also, the Delta Search tab somehow disappeared when I reinstalled my add-ons.
Anyway, your tips are still very helpful. I'll let you know when I've dealt with the malware.
Thanks, BTW :-)

Note that the System Details List attached to the first post showed the presence of a user.js file that is the most likely cause of the delta-search issue (we have seen this before).
*http://kb.mozillazine.org/Preferences_not_saved